Prosody makes human speech natural, intelligible and expressive. Human speech uses prosody in such varied communicative acts as indicating syntactic attachment, topic structure, discourse structure, focus, indirect speech acts, information status, turn-taking behaviors, as well as paralinguistic qualities such as emotion, and sarcasm. The use of prosodic variation to enhance or augment the communication of lexical items is so ubiquitous in speech, human listeners are often unaware of its effects. That is, until a speech synthesis system fails to produce speech with a reasonable approximation of human prosody. Prosodic abnormalities not only negatively impact the naturalness of the synthesized speech, but as prosodic variation is tied to such basic tasks as syntactic attachment and indication of contrast, flouting prosodic norms can lead to degradations of intelligibility. To make synthesized speech as powerful a communication tool as human speech, synthesized speech should at least endeavor to approach human-like prosodic assignment.